Wheel assemblies

ABSTRACT

A wheel assembly comprising a wheel having disc and rim portions and a drive means in the form of a number of circumferentially spaced drive dogs resiliently mounted adjacent the inner periphery of the rim portion of the wheel and arranged to extend substantially parallel to the intended axis of rotation of the wheel.

United States Patent 1 Stimson et al.

Appl. No.: 274,571

Foreign Application Priority Data July 27, 1971 Great Britain 35228/71 US. Cl 301/6 A, 192/55, 192/70.17, 301/6 D, 301/6 E Int. Cl B60b 19/00 Field of Search 301/6 R, 6 D, 6 WB, 6 A, 301/6 CS, 6 E; 188/715; 192/70.2, 55, 70.17

References Cited UNITED STATES PATENTS 5/1930 Eaton 192/70.l7

A 1a l5 l3 Sept. 17, 1974 1,950,700 3/1934 Simmen 192/55 2,161,270 6/1939 Anderson. 192/55 2,925,897 2/1960 Snyder l92/70.2 3,026,979 3/1962 Moore 192/55 3,051,528 8/1962 Rogers 301/6 CS 3,061,050 10/1962 Van l-lorn.... 301/6 A 3,548,984 12/1970 Root 192/70.17

3,605,967 9/1971 Warren 192/70.2 3,739,883 6/1973 Marin 192/70.17

Primary ExaminerRobert S. Ward, Jr. Assistant ExaminerReinhard J. Eisenzopf Attorney, Agent, or -FirmJohn A. Young [5 7] ABSTRACT A wheel assembly comprising a wheel having disc and rim portions and a drive means in the form of a number of cir'cumferentially spaced drive dogs resiliently 14 Claims, 10 Drawing Figures PATENTEDSEPI 11924 SHEET 1 OF 5 FIGI PAIENIEnsEH 7:914

sum 2 0r 5 FIGS.

FIG. 4.

EAIENIE SEPI 71914 SHEET 3 IF 5 PAIENTE sen 71914 SHEET 5 BF 5 FIG. IO.

WHEEL ASSEMBLIES This invention relates to wheel assemblies and particularly to aircraft wheel assemblies in which drive dogs are fastened to the inner periphery of the wheel rim to key with notches formed in the outer peripheries of associated brake rotors.

In certain kinds of aircraft brake, drive dogs of the kind described above have been found to cause damage to the rotors, and this effect is seen particularly when brake rotors of fragile materials such as carbon or beryllium are employed.

One object of the present invention is to provide a wheel assembly incorporating a drive dog construction which is less likely to cause damage to the brake rotors than conventional drive dog arrangements.

According to the invention, a wheel assembly comprises a wheel having disc and rim portions and a drive means in the form of a number of circumferentially spaced drive dogs resiliently mounted adjacent the inner periphery of the rim portion of the wheel and arranged to extend substantially parallel to the intended axis of rotation of the wheel.

Several embodiments of the invention will now be described, by way of example, with reference to FIGS. 1 to 18 of the accompanying drawings in which:

FIG. 1 shows a radial half section through a wheel assembly in accordance with the present invention;

FIG. 2 is an end view in the direction of arrow A of FIG. 1;

FIG. 3 is a sectional view on the line BB of FIG. 2;

FIG. 4 is a sectional view of part of an alternative wheel assembly in accordance with the present invention;

FIG. 5 is a radial section of part of a further alternative wheel assembly in accordance with the present invention;

FIG. 6 is a sectional view on the line C-C of FIG. 5;

FIG. 7 is a sectional view on the line D--D of FIG.

FIG. 8 is a sectional view taken on the same plane as FIG. 6 and illustrating portions of a further wheel assembly; in accordance with the present invention;

FIG. 9 is a radial section of part of a still further wheel assembly in accordance with the present invention;

FIG. 10 is a view in the direction of the arrow E of FIG. 9;

An aircraft wheel assembly, as shown in FIGS. 1 to 3, comprises an aircraft wheel 1 having a disc portion 2, a rim portion 3 provided with tire bead retaining flanges 14 and a number of circumferentially spaced drive dogs 4 resiliently mounted on the wheel adjacent the inner periphery of the wheel rim 3 and arranged to extend substantially parallel to the intended axis of rotation X--X of the wheel.

A brake assembly mounted radially within the wheel rim comprises a series of interleaved rotor and stator discs 5 and 6 in a generally conventional arrangement which incorporates a series of circumferentially-spaced hydraulic actuating piston and cylinder assemblies 7 for squeezing the assembly of discs axially in order to apply the brake.

The rotor and stator discs are of carbon based material, for example carbon fibre reinforced carbon, and

are annular in form. The stator discs 6 are formed with notches on their inner peripheries for engagement with keys 8 formed on an axially extending torque tube 9, and the rotor discs 5 are formed with notches at their outer peripheries for engagement with the drive dogs 4 attached to the wheel.

Each drive dog 4 is secured at one end in a socket 10 formed in the disc portion of the wheel adjacent the rim, the drive dog having a spigot 11 entering a resilient bush 12, which can be formed from natural or synthetic rubber, mounted in the socket. The drive dog is of generally rectangular channel section having the open side of the channel facing towards the rim. and at its end remote from the wheel disc a resilient rectangular rubber shear mounting 13 is provided by means of which the drive dog is secured to a portion 15 of the wheel rim which projects axially outwardly beyond adjacent tyre beadretaining flange 14.

The rubber shear mounting 13 comprises a central metal block 16 secured to the rim by means of an integral screw 17 and a nut 18, and having a pair of rubber blocks 19 bonded one to each side of the metal block and to the inside faces 20 of the substantially radially extending walls 21 of the associated end of the channel.

In an alternative construction, shown in FIG. 4, the rectangular rubber shear mounting 13 is replaced by a circular shear mounting comprising a central metal peg 22 provided with an integral screw 33 and bonded to an outer annular rubber block 24. Block 24 is bonded ina socket 25 formed in the drive dog and the shear mounting is secured to the portion 15 of the wheel rim by a nut 26 which engages screw 23.

In operation, wheel assemblies of the kind described above may, for example on touch-down, be subjected to radial deflection of the wheel rim which causes it to assume a slightly oval shape flattened in the lower portion of the wheel. This distortion causes the drive dogs on the vertical diameter (the 6 oclock and 12 oclock positions) to be moved radially inwardly, while drive dogs near the 4 oclock or 8 oclock positions will be moved radially outwardly. Dogs in other positions will be moved .in both radial and circumferential directions and will also be caused to twist about their axes. Movements of these kinds, in dogs which are rigidly attached to the wheel rim, have been found to cause considerable damage to the disc structure when used with discs formed from relatively fragile materials such as carbon and may also cause binding of the discs on the drive dogs. It has been found that by employing resilient mountings of the kind described above, sufficient tolerance to radial movement of the disc rim can be provided to enable such damage and binding to be greatly reduced or eliminated.

The twisting of the drive dogs about their axes may be prevented by keying the dogs against rotation at their ends which are secured to the wheel disc. This may be effected for example by providing abutment surfaces 31 on the wheel for engagement by corresponding abutment surfaces 32 formed on each dog adjacent the joint at which the dog enters the associated socket 10 in the wheel disc.

In the arrangements described above the movements of the wheel rim are accommodated largely by radial movement of the ends of the dogs secured to the wheel rim, although a degree of circumferential movement may also be permitted by the shear mountings. In an alternative arrangement now to be described the necessary compliance may be wholly or partially circumferential.

One way in which circumferential compliance may be provided using rubber mountings is shown in FIGS. 5 to 7. In this arrangement the end of the drive dog remote from the wheel disc is mounted on the wheel rim by means of an annular rubber and metal mounting 27 comprising inner and outer metal sleeves 28 and 29 and an intermediate annular rubber member 30 bonded therebetween.

The longitudinal axis of the mounting 27 is arranged to extend substantially circumferentially, that is at right angles to the longitudinal axis of the drive dog, and the mounting is secured within a forked portion of the drive dog by a screw 33 which passes through inner sleeve 28 and engages the arms 34 and 35 of the forked portion of the drive dog. The mounting is secured to the extended portion 15 of the wheel rim by means of an integrally formed screw 36 and a nut 37. Outer sleeve 29 is provided with a flat abutment surface 38 for clamping engagement with the wheel rim.

In an alternative arrangement, shown in FIG. 8, for providing circumferential compliance the rubber mounting 27 is replaced by two compression springs 39, e.g. Belleville washers, flanking a metal block 40, slidably mounted on a screw 41 spanning the arms 34 and 35 of the fork portion of the drive dog. The metal block is secured to the extended portion 15 of the wheel rim by an integrally formed screw 41 and a nut 42.

In a further alternative mounting arrangement shown in FIGS. and 11 the ends of the drive dogs remote from the disc portion of the wheel are secured to a continuous metal strip 51 (or series of strips) which extend around the inner circumference of the rim extension and is secured thereto at a series of positions intermediate the dogs. The portion of the strip associated with each dog is of V-shaped form, the ends of the arms of each V-shaped portion being secured to the wheel rim extension 15 by rivets 52 and the apex of the V-shaped portion being arranged to extend towards the wheel disc and being secured to each drive dog 53 by a rivet 54. The V-shaped portion is also bent radially inwardly towards its apex, and thus provides a radially flexible mounting which is also capable of limited circumferential compliance. The strip may be arranged in various alternative forms (not shown), for example the apices of the V-shaped portions may be linked by a circumferential strip which may be integral with the V-shaped portions.

Although in all the mounting arrangements described above the drive dogs are resiliently mounted at one end on the wheel rim and the other end on the wheel disc it will be understood by those skilled in the art that both ends of the drive dogs could alternatively be resiliently mounted on the wheel rim.

Having now described our invention what we claim is:

1. A wheel assembly comprising a wheel having disc and rim portions, drive means consisting of a number of circumferentially spaced drive dogs disposed adjacent the inner periphery of the rim portion of said wheel and arranged to extend substantially parallel to the axis of rotation of said wheel, and means for resiliently mounting each dog to said wheel and comprising at least one resilient element disposed between the wheel and the respective one of said drive dogs.

2. A wheel assembly according to claim 1 in which the drive dogs are resiliently mounted at one end on the rim portion of the wheel and at the other end on the disc portion of the wheel.

3. A wheel assembly according to claim 1 in which the drive dogs are resiliently mounted at both ends on the rim portion of the wheel.

4. A wheel assembly according to claim l in which each drive dog is resiliently mounted on the wheel by means of at least one rubber element disposed between the drive dog and the wheel.

5. A wheel assembly according to claim 1 in which the ends of the drive dogs adjacent the disc portion of the wheel are each mounted on the wheel by means of a spigot arranged to enter a rubber bush mounted in a socket formed in the disc portion of the wheel.

6. A wheel assembly according to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of a rubber shear mounting comprising a central metal block, secured to the rim portion of the wheel and a pair of outer rubber blocks bonded to the metal block and drive dog one on each side of the metal block.

7. A wheel assembly according to claim 6 in which the drive dogs are of a generally rectangular channel section with the open side of the channel facing the rim portion of the wheel and the rubber blocks of the shear mounting are bonded to the inside faces of the substantially radially extending walls of the channel.

8. A wheel assembly according to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of a rubber shear mounting comprising a central metal peg secured to the rim portion of the wheel and an outer annular rubber block bonded to the peg and to the drive dog.

9. A wheel assembly according to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of an annular rubber and metal mount comprising inner and outer metal sleeves with an intermediate annular rubber. member bonded therebetween, the longitudinal axis of the mount being arranged to extend substantially circumferentially with respect to the wheel and the outer sleeve being secured to the wheel rim and the inner sleeve to the drive dog.

10. A wheel assembly accordig to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of two compression springs mounted one on each side of a metal block, the longitudinal axes of the springs being arranged to extend substantially circumferentially with respect to the wheel, the block being secured to the rim portion of the wheel and the springs being arranged to act between the drive dog and the block.

.11. A wheel assembly according to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of a flexible strip of metal secured to the drive dog and to the rim portion of the wheel.

12. A wheel assembly according to claim 11 in which a continuous strip of metal extends around the inner circumference of the rim portion of the wheel, the

drive dogs being secured to the strip at circumferen tially spaced positions.

13. A wheel assembly according to claim 12 in which the portion of the strip associated with each drive dog is of V-shaped form, the ends of the arms of the V- shaped portion being secured to the rim portion of the wheel and the apex of the V-shaped portion being arprevent damage to the disc structure. 

1. A wheel assembly comprising a wheel having disc and rim portions, drive means consisting of a number of circumferentially spaced drive dogs disposed adjacent the inner periphery of the rim portion of said wheel and arranged to extend substantially parallel to the axis of rotation of said wheel, and means for resiliently mounting each dog to said wheel and comprising at least one resilient element disposed between the wheel and the respective one of said drive dogs.
 2. A wheel assembly according to claim 1 in which the drive dogs are resiliently mounted at one end on the rim portion of the wheel and at the other end on the disc portion of the wheel.
 3. A wheel assembly according to claim 1 in which the drive dogs are resiliently mounted at both ends on the rim portion of the wheel.
 4. A wheel assembly according to claim 1 in which each drive dog is resiliently mounted on the wheel by means of at least one rubber element disposed between the drive dog and the wheel.
 5. A wheel assembly according to claim 1 in which the ends of the drive dogs adjacent the disc portion of the wheel are each mounted on the wheel by means of a spigot arranged to enter a rubber bush mounted in a socket formed in the disc portion of the wheel.
 6. A wheel assembly according to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of a rubber shear mounting comprising a central metal block, secured to the rim portion of the wheel and a pair of outer rubber blocks bonded to the metal block and drive dog one on each side of the metal block.
 7. A wheel assembly according to claim 6 in which the drive dogs are of a generally rectangular channel section with the open side of the channel facing the rim portion of the wheel and the rubber blocks of the shear mounting are bonded to the inside faces of the substantially radially extending walls of the channel.
 8. A wheel assembly according to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of a rubber shear mounting comprising a central metal peg secured to the rim portion of the wheel and an outer annular rubber block bonded to the peg and to the drive dog.
 9. A wheel assembly according to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of an annular rubber and metal mount comprising inner and outer metal sleeves with an intermediate annular rubber member bonded therebetween, the longitudinal axis of the mount being arranged to extend substantially circumferentially with respect to the wheel and the outer sleeve being secured to the wheel rim and the inner sleeve to the drive dog.
 10. A wheel assembly accordig to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of two compression springs mounted one on each side of a metal block, the longitudinal axes of the springs being arranged to extend substantially circumferentially with respect to the wheel, the block being secured to the rim portion of the wheel and the springs being arranged to act between the drive dog and the block.
 11. A wheel assembly according to claim 1 in which the ends of the drive dogs remote from the disc portion of the wheel are each mounted on the wheel by means of a flexible strip of metal secured to the drive dog and to the rim portion of the wheel.
 12. A wheel assembly according to claim 11 in which a continuous strip of metal extends around the inner circumference of the rim portion of the wheel, the drive dogs being secured to the strip at circumferentially spaced positions.
 13. A wheel assembly according to claim 12 in which the portion of the strip associated with each drive dog is of V-shaped form, the ends of the arms of the V-shaped portion being secured to the rim portion of the wheel and the apex of the V-shaped portion being arranged to extend towards the disc portion of the wheel and being secured to the drive dog.
 14. The wheel assembly in accordance with claim 1 wherein said resilient element provides both radial and circumferential movement of each said drive dog to prevent damage to the disc structure. 